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Yeo XY, Kwon S, Rinai KR, Lee S, Jung S, Park R. A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment. Antioxidants (Basel) 2024; 13:598. [PMID: 38790703 PMCID: PMC11118506 DOI: 10.3390/antiox13050598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/26/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.
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Affiliation(s)
- Xin Yi Yeo
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Soohyun Kwon
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
- Department of BioNanotechnology, Gachon University, Seongnam 13120, Republic of Korea
| | - Kimberley R. Rinai
- Department of Life Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Sungsu Lee
- Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Hospital and Medical School, Gwangju 61469, Republic of Korea;
| | - Sangyong Jung
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Raekil Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 61005, Republic of Korea
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Tsukada K, Nishio SY, Takumi Y, Usami SI. Comparison of vestibular function in hereditary hearing loss patients with GJB2, CDH23, and SLC26A4 variants. Sci Rep 2024; 14:10596. [PMID: 38720048 PMCID: PMC11078969 DOI: 10.1038/s41598-024-61442-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 05/06/2024] [Indexed: 05/12/2024] Open
Abstract
To investigate the association between hereditary hearing loss and vestibular function, we compared vestibular function and symptoms among patients with GJB2, SLC26A4, and CDH23 variants. Thirty-nine patients with sensory neural hearing loss (11 males and 28 females) with biallelic pathogenic variants in either GJB2, SLC26A4, or CDH23 were included in this study (13 GJB2, 15 SLC26A4, and 11 CDH23). The patients were examined using caloric testing and cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP). We also compared vestibular function and symptoms between patients with these gene variants and 78 normal-hearing ears without vestibular symptoms as controls. The frequency of semicircular canal hypofunction in caloric testing was higher in patients with SLC26A4 variants (47%) than in those with GJB2 (0%) and CDH23 variants (27%). According to the cVEMP results, 69% of patients with GJB2 variants had saccular hypofunction, a significantly higher proportion than in those carrying other variants (SLC26A4, 20%; CDH23, 18%). In oVEMP, which reflects utricular function, no difference was observed in the frequency of hypofunction among the three genes (GJB2, 15%; SLC26A4, 40%; and CDH23, 36%). Hence, discernable trends indicate vestibular dysfunction associated with each gene.
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Affiliation(s)
- Keita Tsukada
- Department of Otorhinolaryngology Head and Neck Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
| | - Shin-Ya Nishio
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Yutaka Takumi
- Department of Otorhinolaryngology Head and Neck Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
| | - Shin-Ichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan
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Ito T, Watanabe H, Honda K, Fujikawa T, Kitamura K, Tsutsumi T. The role of SLC26A4 in bony labyrinth development and otoconial mineralization in mouse models. Front Mol Neurosci 2024; 17:1384764. [PMID: 38742227 PMCID: PMC11089141 DOI: 10.3389/fnmol.2024.1384764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024] Open
Abstract
Inner ear malformations are predominantly attributed to developmental arrest during the embryonic stage of membranous labyrinth development. Due to the inherent difficulty in clinically assessing the status of the membranous labyrinth, these malformations are diagnosed with radiographic imaging, based on the morphological characteristics of the bony labyrinth. While extensive research has elucidated the intricacies of membranous labyrinth development in mouse models, comprehensive investigations into the developmental trajectory of the bony labyrinth, especially about its calcification process, have been notably lacking. One of the most prominent types of inner ear malformations is known as incomplete partition (IP), characterized by nearly normal external cochlear appearance but pronounced irregularities in the morphology of the modiolus and inter-scalar septa. IP type II (IP-II), also known as Mondini dysplasia, is generally accompanied by an enlargement of the vestibular aqueduct and is primarily attributed to mutations in the SLC26A4 gene. In the case of IP-II, the modiolus and inter-scalar septa of the cochlear apex are underdeveloped or missing, resulting in the manifestation of a cystic structure on radiographic imaging. In this overview, we not only explore the normal development of the bony labyrinth in mice but also present our observations on otolith mineralization. Furthermore, we investigated the specifics of bony labyrinth and otolith mineralization in Slc26a4-deficient mice, which served as an animal model for IP-II. We ensured that these findings promise to provide valuable insights for the establishment of therapeutic interventions, optimal timing, targeted sites, and preventive measures when considering the management of this condition.
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Affiliation(s)
- Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ken Kitamura
- Department of Otorhinolaryngology, Chigasaki Chuo Hospital, Kanagawa, Japan
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
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Tallandier V, Merlen L, Chalansonnet M, Boucard S, Thomas A, Venet T, Pouyatos B. Three-dimensional cultured ampullae from rats as a screening tool for vestibulotoxicity: Proof of concept using styrene. Toxicology 2023; 495:153600. [PMID: 37516305 DOI: 10.1016/j.tox.2023.153600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Numerous ototoxic drugs, such as some antibiotics and chemotherapeutics, are both cochleotoxic and vestibulotoxic (causing hearing loss and vestibular disorders). However, the impact of some industrial cochleotoxic compounds on the vestibular receptor, if any, remains unknown. As in vivo studies are long and expensive, there is considerable need for predictive and cost-effective in vitro models to test ototoxicity. Here, we present an organotypic model of cultured ampullae harvested from rat neonates. When cultured in a gelatinous matrix, ampulla explants form an enclosed compartment that progressively fills with a high-potassium (K+) endolymph-like fluid. Morphological analyses confirmed the presence of a number of cell types, sensory epithelium, secretory cells, and canalar cells. Treatments with inhibitors of potassium transporters demonstrated that the potassium homeostasis mechanisms were functional. To assess the potential of this model to reveal the toxic effects of chemicals, explants were exposed for either 2 or 72 h to styrene at a range of concentrations (0.5-1 mM). In the 2-h exposure condition, K+ concentration was significantly reduced, but ATP levels remained stable, and no histological damage was visible. After 72 h exposure, variations in K+ concentration were associated with histological damage and decreased ATP levels. This in vitro 3D neonatal rat ampulla model therefore represents a reliable and rapid means to assess the toxic properties of industrial compounds on this vestibular tissue, and can be used to investigate the specific underlying mechanisms.
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Affiliation(s)
- V Tallandier
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - L Merlen
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - M Chalansonnet
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France.
| | - S Boucard
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - A Thomas
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - T Venet
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - B Pouyatos
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
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Koh JY, Affortit C, Ranum PT, West C, Walls WD, Yoshimura H, Shao JQ, Mostaert B, Smith RJH. Single-cell RNA-sequencing of stria vascularis cells in the adult Slc26a4 -/- mouse. BMC Med Genomics 2023; 16:133. [PMID: 37322474 PMCID: PMC10268361 DOI: 10.1186/s12920-023-01549-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
BACKGROUND The primary pathological alterations of Pendred syndrome are endolymphatic pH acidification and luminal enlargement of the inner ear. However, the molecular contributions of specific cell types remain poorly characterized. Therefore, we aimed to identify pH regulators in pendrin-expressing cells that may contribute to the homeostasis of endolymph pH and define the cellular pathogenic mechanisms that contribute to the dysregulation of cochlear endolymph pH in Slc26a4-/- mice. METHODS We used single-cell RNA sequencing to identify both Slc26a4-expressing cells and Kcnj10-expressing cells in wild-type (WT, Slc26a4+/+) and Slc26a4-/- mice. Bioinformatic analysis of expression data confirmed marker genes defining the different cell types of the stria vascularis. In addition, specific findings were confirmed at the protein level by immunofluorescence. RESULTS We found that spindle cells, which express pendrin, contain extrinsic cellular components, a factor that enables cell-to-cell communication. In addition, the gene expression profile informed the pH of the spindle cells. Compared to WT, the transcriptional profiles in Slc26a4-/- mice showed downregulation of extracellular exosome-related genes in spindle cells. Immunofluorescence studies in spindle cells of Slc26a4-/- mice validated the increased expression of the exosome-related protein, annexin A1, and the clathrin-mediated endocytosis-related protein, adaptor protein 2. CONCLUSION Overall, cell isolation of stria vascularis from WT and Slc26a4-/- samples combined with cell type-specific transcriptomic analyses revealed pH-dependent alternations in spindle cells and intermediate cells, inspiring further studies into the dysfunctional role of stria vascularis cells in SLC26A4-related hearing loss.
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Affiliation(s)
- Jin-Young Koh
- Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, University of Iowa, Iowa City, IA, USA
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Corentin Affortit
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Paul T Ranum
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, USA
| | - Cody West
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - William D Walls
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Hidekane Yoshimura
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, Shinshu University School of Medicine, Matsumoto, Japan
| | - Jian Q Shao
- Central Microscopy Research Facility, University of Iowa, Iowa City, IA, USA
| | - Brian Mostaert
- Department of Otolaryngology, Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Richard J H Smith
- Roy J. Carver Department of Biomedical Engineering, College of Engineering, University of Iowa, University of Iowa, Iowa City, IA, USA.
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Department of Otolaryngology, Head and Neck Surgery, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Xie Z, Ma XH, Bai QF, Tang J, Sun JH, Jiang F, Guo W, Wang CM, Yang R, Wen YC, Wang FY, Chen YX, Zhang H, He DZ, Kelley MW, Yang S, Zhang WJ. ZBTB20 is essential for cochlear maturation and hearing in mice. Proc Natl Acad Sci U S A 2023; 120:e2220867120. [PMID: 37279265 PMCID: PMC10268240 DOI: 10.1073/pnas.2220867120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 04/25/2023] [Indexed: 06/08/2023] Open
Abstract
The mammalian cochlear epithelium undergoes substantial remodeling and maturation before the onset of hearing. However, very little is known about the transcriptional network governing cochlear late-stage maturation and particularly the differentiation of its lateral nonsensory region. Here, we establish ZBTB20 as an essential transcription factor required for cochlear terminal differentiation and maturation and hearing. ZBTB20 is abundantly expressed in the developing and mature cochlear nonsensory epithelial cells, with transient expression in immature hair cells and spiral ganglion neurons. Otocyst-specific deletion of Zbtb20 causes profound deafness with reduced endolymph potential in mice. The subtypes of cochlear epithelial cells are normally generated, but their postnatal development is arrested in the absence of ZBTB20, as manifested by an immature appearance of the organ of Corti, malformation of tectorial membrane (TM), a flattened spiral prominence (SP), and a lack of identifiable Boettcher cells. Furthermore, these defects are related with a failure in the terminal differentiation of the nonsensory epithelium covering the outer border Claudius cells, outer sulcus root cells, and SP epithelial cells. Transcriptome analysis shows that ZBTB20 regulates genes encoding for TM proteins in the greater epithelial ridge, and those preferentially expressed in root cells and SP epithelium. Our results point to ZBTB20 as an essential regulator for postnatal cochlear maturation and particularly for the terminal differentiation of cochlear lateral nonsensory domain.
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Affiliation(s)
- Zhifang Xie
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Xian-Hua Ma
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Qiu-Fang Bai
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Jie Tang
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Jian-He Sun
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Fei Jiang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
| | - Wei Guo
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Chen-Ma Wang
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Rui Yang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Yin-Chuan Wen
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Fang-Yuan Wang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Yu-Xia Chen
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Hai Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - David Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE68178
| | | | - Shiming Yang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
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Watanabe H, Ito T, Aoki N, Bai J, Honda K, Kawashima Y, Fujikawa T, Ikeda T, Tsutsumi T. Quantitative analysis and correlative evaluation of video-oculography, micro-computed tomography, and histopathology in Pendrin-null mice. Neurobiol Dis 2023; 183:106194. [PMID: 37295562 DOI: 10.1016/j.nbd.2023.106194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023] Open
Abstract
Patients with SLC26A4 mutations exhibit highly variable hearing loss and vestibular dysfunction. Although Slc26a4 mutant mice similarly exhibit vestibular deficits, including circling behavior, head tilting, and torticollis, the underlying pathogenesis of the vestibular symptoms remains unclear, hindering its effective management for patients with SLC26A4 mutations. In this study, we evaluated the equilibrium function using the inspection equipment, which can record eye movements against rotational, gravitational, and thermal stimulations. Moreover, we correlated the degree of functional impairment with the morphological alterations observed in Slc26a4Δ/Δ mice. The rotational stimulus and ice water caloric tests revealed considerable impairment of the semicircular canal, while the tilted gravitational stimulus test showed a severe functional decline of the otolithic system in Slc26a4Δ/Δ mice. Generally, the degree of impairment was more severe in circling Slc26a4Δ/Δ mice than in non-circling Slc26a4Δ/Δ mice. In non-circling Slc26a4Δ/Δ mice, the semicircular canal function was normal. Micro-computed tomography results showed enlargement of the vestibular aqueduct and bony semicircular canals but no correlative relationship between the severity of the caloric response and the size of bony labyrinths. Giant otoconia and a significant decrease in total otolith volume in the saccule and utricle were observed in Slc26a4Δ/Δ mice. However, the giant otoconia were not overly dislocated in the bony otolithic system and ectopic otoconia were absent in the semicircular canal. The number and morphology of the utricular hair cells in Slc26a4Δ/Δ mice were not significantly reduced compared to those in Slc26a4Δ/+ mice. Collectively, we can conclude that vestibular impairments are mainly associated with otoconia formation and morphology rather than hair cell degeneration. In addition, severe disturbances of semicircular canals cause circling behavior in Slc26a4Δ/Δ mice. Our comprehensive morphological and functional assessments apply to mouse models of other genetic diseases with vestibular impairment.
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Affiliation(s)
- Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan; Department of Otorhinolaryngology, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
| | - Natsuki Aoki
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Jing Bai
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Yoshiyuki Kawashima
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takuo Ikeda
- Department of Otorhinolaryngology, Tsudumigaura Medical Center for Children with disabilities, 752-4 Kume, Shunan-shi, Yamaguchi 745-0801, Japan
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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8
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Bałdyga N, Oziębło D, Gan N, Furmanek M, Leja ML, Skarżyński H, Ołdak M. The Genetic Background of Hearing Loss in Patients with EVA and Cochlear Malformation. Genes (Basel) 2023; 14:genes14020335. [PMID: 36833263 PMCID: PMC9957411 DOI: 10.3390/genes14020335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
The most frequently observed congenital inner ear malformation is enlarged vestibular aqueduct (EVA). It is often accompanied with incomplete partition type 2 (IP2) of the cochlea and a dilated vestibule, which together constitute Mondini malformation. Pathogenic SLC26A4 variants are considered the major cause of inner ear malformation but the genetics still needs clarification. The aim of this study was to identify the cause of EVA in patients with hearing loss (HL). Genomic DNA was isolated from HL patients with radiologically confirmed bilateral EVA (n = 23) and analyzed by next generation sequencing using a custom HL gene panel encompassing 237 HL-related genes or a clinical exome. The presence and segregation of selected variants and the CEVA haplotype (in the 5' region of SLC26A4) was verified by Sanger sequencing. Minigene assay was used to evaluate the impact of novel synonymous variant on splicing. Genetic testing identified the cause of EVA in 17/23 individuals (74%). Two pathogenic variants in the SLC26A4 gene were identified as the cause of EVA in 8 of them (35%), and a CEVA haplotype was regarded as the cause of EVA in 6 of 7 patients (86%) who carried only one SLC26A4 genetic variant. In two individuals with a phenotype matching branchio-oto-renal (BOR) spectrum disorder, cochlear hypoplasia resulted from EYA1 pathogenic variants. In one patient, a novel variant in CHD7 was detected. Our study shows that SLC26A4, together with the CEVA haplotype, accounts for more than half of EVA cases. Syndromic forms of HL should also be considered in patients with EVA. We conclude that to better understand inner ear development and the pathogenesis of its malformations, there is a need to look for pathogenic variants in noncoding regions of known HL genes or to link them with novel candidate HL genes.
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Affiliation(s)
- Natalia Bałdyga
- Department of Genetics, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
- Doctoral School of Translational Medicine, Medical Centre of Postgraduate Education, 01-813 Warsaw, Poland
| | - Dominika Oziębło
- Department of Genetics, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
| | - Nina Gan
- Department of Genetics, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
- Doctoral School of Translational Medicine, Medical Centre of Postgraduate Education, 01-813 Warsaw, Poland
| | - Mariusz Furmanek
- Bioimaging Research Center, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
| | - Marcin L. Leja
- Department of Genetics, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
| | - Henryk Skarżyński
- Oto-Rhino-Laryngology Surgery Clinic, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
| | - Monika Ołdak
- Department of Genetics, Institute of Physiology and Pathology of Hearing, 02-042 Warsaw, Poland
- Correspondence: ; Tel.: +48-22-356-03-66
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Petralia RS, Wang YX. Review of Post-embedding Immunogold Methods for the Study of Neuronal Structures. Front Neuroanat 2021; 15:763427. [PMID: 34720893 PMCID: PMC8551803 DOI: 10.3389/fnana.2021.763427] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/28/2021] [Indexed: 01/03/2023] Open
Abstract
The post-embedding immunogold (PI) technique for immunolabeling of neuronal tissues utilizing standard thin-section transmission electron microscopy (TEM) continues to be a prime method for understanding the functional localization of key proteins in neuronal function. Its main advantages over other immunolabeling methods for thin-section TEM are (1) fairly accurate and quantifiable localization of proteins in cells; (2) double-labeling of sections using two gold particle sizes; and (3) the ability to perform multiple labeling for different proteins by using adjacent sections. Here we first review in detail a common method for PI of neuronal tissues. This method has two major parts. First, we describe the freeze-substitution embedding method: cryoprotected tissue is frozen in liquid propane via plunge-freezing, and is placed in a freeze-substitution instrument in which the tissue is embedded in Lowicryl at low temperatures. We highlight important aspects of freeze-substitution embedding. Then we outline how thin sections of embedded tissue on grids are labeled with a primary antibody and a secondary gold particle-conjugated antibody, and the particular problems encountered in TEM of PI-labeled sections. In the Discussion, we compare our method both to earlier PI methods and to more recent PI methods used by other laboratories. We also compare TEM immunolabeling using PI vs. various pre-embedding immunolabeling methods, especially relating to neuronal tissue.
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Affiliation(s)
- Ronald S. Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
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Ito T, Fujikawa T, Honda K, Makabe A, Watanabe H, Bai J, Kawashima Y, Miwa T, Griffith AJ, Tsutsumi T. Cochlear Pathomorphogenesis of Incomplete Partition Type II in Slc26a4-Null Mice. J Assoc Res Otolaryngol 2021; 22:681-691. [PMID: 34622375 DOI: 10.1007/s10162-021-00812-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 08/09/2021] [Indexed: 11/24/2022] Open
Abstract
Incomplete partition type II (IP-II) is frequently identified in ears with SLC26A4 mutations. Cochleae with IP-II are generally observed to have 1½ turns; the basal turns are normally formed, and the apical turn is dilated or cystic. The objective of this study was to characterize the pathomorphogenesis of the IP-II cochlear anomaly in Slc26a4-null mice. Otic capsules were dissected from Slc26a4Δ/+ and Slc26a4Δ/Δ mice at 1 and 8 days of age and at 1 and 3 months of age. X-ray micro-computed tomography was used to image samples. We used a multiplanar view and three-dimensional reconstructed models to calculate the cochlear duct length, cochlear turn rotation angle, and modiolus tilt angle. The number of inner hair cells was counted, and the length of the cochlear duct was measured in a whole-mount preparation of the membranous labyrinth. X-ray micro-computed tomography mid-modiolar planar views demonstrated cystic apical turns in Slc26a4Δ/Δ mice resulting from the loss or deossification of the interscalar septum, which morphologically resembles IP-II in humans. Planes vertical to the modiolus showed a similar mean rotation angle between Slc26a4Δ/+ and Slc26a4Δ/Δ mice. In contrast, the mean cochlear duct length and mean number of inner hair cells in Slc26a4Δ/Δ mice were significantly smaller than in Slc26a4Δ/+ mice. In addition, there were significant differences in the mean tilt angle and mean width of the modiolus. Our analysis of Slc26a4-null mice suggests that IP-II in humans reflects loss or deossification of the interscalar septum but not a decreased number of cochlear turns.
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Affiliation(s)
- Taku Ito
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan.
| | - Taro Fujikawa
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Ayane Makabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Hiroki Watanabe
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Jing Bai
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Yoshiyuki Kawashima
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
| | - Toru Miwa
- Department of Otolaryngology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, 2-4-20 Ogimachi, Kita-ku, Osaka, 530-8480, Japan
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute On Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.,Departments of Otolaryngology and Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Takeshi Tsutsumi
- Department of Otorhinolaryngology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519, Tokyo, Japan
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11
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An L1 retrotransposon insertion-induced deafness mouse model for studying the development and function of the cochlear stria vascularis. Proc Natl Acad Sci U S A 2021; 118:2107933118. [PMID: 34583993 DOI: 10.1073/pnas.2107933118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2021] [Indexed: 01/23/2023] Open
Abstract
Dysregulation of ion and potential homeostasis in the scala media is the most prevalent cause of hearing loss in mammals. However, it is not well understood how the development and function of the stria vascularis regulates this fluid homeostasis in the scala media. From a mouse genetic screen, we characterize a mouse line, named 299, that displays profound hearing impairment. Histology suggests that 299 mutant mice carry a severe, congenital structural defect of the stria vascularis. The in vivo recording of 299 mice using double-barreled electrodes shows that endocochlear potential is abolished and potassium concentration is reduced to ∼20 mM in the scala media, a stark contrast to the +80 mV endocochlear potential and the 150 mM potassium concentration present in healthy control mice. Genomic analysis revealed a roughly 7-kb-long, interspersed nuclear element (LINE-1 or L1) retrotransposon insertion on chromosome 11. Strikingly, the deletion of this L1 retrotransposon insertion from chromosome 11 restored the hearing of 299 mutant mice. In summary, we characterize a mouse model that enables the study of stria vascularis development and fluid homeostasis in the scala media.
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12
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Smits JJ, de Bruijn SE, Lanting CP, Oostrik J, O'Gorman L, Mantere T, Cremers FPM, Roosing S, Yntema HG, de Vrieze E, Derks R, Hoischen A, Pegge SAH, Neveling K, Pennings RJE, Kremer H. Exploring the missing heritability in subjects with hearing loss, enlarged vestibular aqueducts, and a single or no pathogenic SLC26A4 variant. Hum Genet 2021; 141:465-484. [PMID: 34410491 PMCID: PMC9035008 DOI: 10.1007/s00439-021-02336-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/09/2021] [Indexed: 12/11/2022]
Abstract
Pathogenic variants in SLC26A4 have been associated with autosomal recessive hearing loss (arHL) and a unilateral or bilateral enlarged vestibular aqueduct (EVA). SLC26A4 is the second most frequently mutated gene in arHL. Despite the strong genotype–phenotype correlation, a significant part of cases remains genetically unresolved. In this study, we investigated a cohort of 28 Dutch index cases diagnosed with HL in combination with an EVA but without (M0) or with a single (M1) pathogenic variant in SLC26A4. To explore the missing heritability, we first determined the presence of the previously described EVA-associated haplotype (Caucasian EVA (CEVA)), characterized by 12 single nucleotide variants located upstream of SLC26A4. We found this haplotype and a delimited V1-CEVA haplotype to be significantly enriched in our M1 patient cohort (10/16 cases). The CEVA haplotype was also present in two M0 cases (2/12). Short- and long-read whole genome sequencing and optical genome mapping could not prioritize any of the variants present within the CEVA haplotype as the likely pathogenic defect. Short-read whole-genome sequencing of the six M1 cases without this haplotype and the two M0/CEVA cases only revealed previously overlooked or misinterpreted splice-altering SLC26A4 variants in two cases, who are now genetically explained. No deep-intronic or structural variants were identified in any of the M1 subjects. With this study, we have provided important insights that will pave the way for elucidating the missing heritability in M0 and M1 SLC26A4 cases. For pinpointing the pathogenic effect of the CEVA haplotype, additional analyses are required addressing defect(s) at the RNA, protein, or epigenetic level.
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Affiliation(s)
- Jeroen J Smits
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Suzanne E de Bruijn
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cornelis P Lanting
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jaap Oostrik
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Luke O'Gorman
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Tuomo Mantere
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Laboratory of Cancer Genetics and Tumor Biology, Cancer and Translational Medicine Research Unit and Biocenter Oulu, University of Oulu, Oulu, Finland
| | | | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helger G Yntema
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Erik de Vrieze
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Center for Infectious Diseases (RCI), Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Expertise Center for Immunodeficiency and Autoinflammation and Center for Infectious Disease (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sjoert A H Pegge
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Ronald J E Pennings
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hannie Kremer
- Hearing and Genes, Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands. .,Department of Human Genetics, Radboud University Medical Center, Internal Postal Code 855, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands. .,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
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13
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Honda K, Griffith AJ. Genetic architecture and phenotypic landscape of SLC26A4-related hearing loss. Hum Genet 2021; 141:455-464. [PMID: 34345941 DOI: 10.1007/s00439-021-02311-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/29/2021] [Indexed: 12/15/2022]
Abstract
Mutations of coding regions and splice sites of SLC26A4 cause Pendred syndrome and nonsyndromic recessive hearing loss DFNB4. SLC26A4 encodes pendrin, a transmembrane exchanger of anions and bases. The mutant SLC26A4 phenotype is characterized by inner ear malformations, including an enlarged vestibular aqueduct (EVA), incomplete cochlear partition type II and modiolar hypoplasia, progressive and fluctuating hearing loss, and vestibular dysfunction. A thyroid iodine organification defect can lead to multinodular goiter and distinguishes Pendred syndrome from DFNB4. Pendred syndrome and DFNB4 are each inherited as an autosomal recessive trait caused by biallelic mutations of SLC26A4 (M2). However, there are some EVA patients with only one detectable mutant allele (M1) of SLC26A4. In most European-Caucasian M1 patients, there is a haplotype that consists of 12 variants upstream of SLC26A4, called CEVA (Caucasian EVA), which acts as a pathogenic recessive allele in trans to mutations affecting the coding regions or splice sites of SLC26A4. This combination of an M1 genotype with the CEVA haplotype is associated with a less severe phenotype than the M2 genotype. The phenotype in EVA patients with no mutant alleles of SLC26A4 (M0) has a very low recurrence probability and is likely to be caused by other factors.
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Affiliation(s)
- Keiji Honda
- Department of Otorhinolaryngology, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Andrew J Griffith
- Department of Otolaryngology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
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14
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Abstract
Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.
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Affiliation(s)
- Justine M Renauld
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Martin L Basch
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve School of Medicine, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio.,Department of Otolaryngology, Head & Neck Surgery, University Hospitals, Cleveland, Ohio
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15
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Transcriptomic Analysis Reveals an Altered Hcy Metabolism in the Stria Vascularis of the Pendred Syndrome Mouse Model. Neural Plast 2021; 2021:5585394. [PMID: 33959158 PMCID: PMC8075705 DOI: 10.1155/2021/5585394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/19/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
Purpose Slc26a4-/- mice exhibit severer defects in the development of the cochlea and develop deafness, while the underlying mechanisms responsible for these effects remain unclear. Our study was to investigate the potential mechanism linking SLC26A4 deficiency to hearing loss. Materials and Methods RNA sequencing was applied to analyze the differential gene expression of the stria vascularis (SV) from wildtype and Slc26a4-/- mice. GO and KEGG pathway analysis were performed. Quantitative RT-PCR was applied to validate the expression of candidate genes affected by Slc26a4. ELISA and immunofluorescence technique were used to detect the homocysteine (Hcy) level in serum, brain, and SV, respectively. Results 183 upregulated genes and 63 downregulated genes were identified in the SV associated with Slc26a4 depletion. Transcriptomic profiling revealed that Slc26a4 deficiency significantly affected the expression of genes associated with cell adhesion, transmembrane transport, and the biogenesis of multicellular organisms. The SV from Slc26a4-/- mice exhibited a higher expression of Bhmt mRNAs, as well as altered homocysteine (Hcy) metabolism. Conclusions The altered expression of Bhmt results in a dramatic change in multiple biochemical reactions and a disruption of nutrient homeostasis in the endolymph which may contribute to hearing loss of Slc26a4 knockout mouse.
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16
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Absence of Endolymphatic Sac Ion Transport Proteins in Large Vestibular Aqueduct Syndrome-A Human Temporal Bone Study. Otol Neurotol 2021; 41:e1256-e1263. [PMID: 32890293 DOI: 10.1097/mao.0000000000002832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Epithelial ion transport pathologies of the endolymphatic sac (ES) are associated with large vestibular aqueduct syndrome (LVAS). BACKGROUND LVAS is defined by the pathognomonic features of a widened bony vestibular aqueduct (VA) and an enlarged ES. The underlying cause of its associated cochleovestibular symptoms remains elusive. Disturbances in epithelial ion transport in the enlarged ES, affecting inner ear fluid regulation, were proposed as a possible pathophysiology. However, although respective epithelial ion transport pathologies have been demonstrated in the enlarged ES from transgenic LVAS mouse models, these pathologies have not been investigated in human LVAS cases. METHODS Histological and immunohistochemical analysis of the enlarged ES epithelium in postmortem temporal bones from two individuals with a clinical diagnosis of LVAS. RESULTS The enlarged ES epithelium demonstrated an overall atypical epithelial differentiation and a lack of the immunolocalization of signature ion transport proteins. Notably, in both cases, a rudimentary branch of the ES with a typically differentiated ES epithelium was present. CONCLUSIONS The described cellular and molecular pathologies of the enlarged ES in humans provide evidence of epithelial transport pathology as one potential cause of cochleovestibular symptoms in LVAS. The present findings also emphasize the clinical relevance of already established LVAS mouse models.
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17
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Eckert MA, Harris KC, Lang H, Lewis MA, Schmiedt RA, Schulte BA, Steel KP, Vaden KI, Dubno JR. Translational and interdisciplinary insights into presbyacusis: A multidimensional disease. Hear Res 2021; 402:108109. [PMID: 33189490 PMCID: PMC7927149 DOI: 10.1016/j.heares.2020.108109] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 10/19/2020] [Accepted: 10/25/2020] [Indexed: 12/18/2022]
Abstract
There are multiple etiologies and phenotypes of age-related hearing loss or presbyacusis. In this review we summarize findings from animal and human studies of presbyacusis, including those that provide the theoretical framework for distinct metabolic, sensory, and neural presbyacusis phenotypes. A key finding in quiet-aged animals is a decline in the endocochlear potential (EP) that results in elevated pure-tone thresholds across frequencies with greater losses at higher frequencies. In contrast, sensory presbyacusis appears to derive, in part, from acute and cumulative effects on hair cells of a lifetime of environmental exposures (e.g., noise), which often result in pronounced high frequency hearing loss. These patterns of hearing loss in animals are recognizable in the human audiogram and can be classified into metabolic and sensory presbyacusis phenotypes, as well as a mixed metabolic+sensory phenotype. However, the audiogram does not fully characterize age-related changes in auditory function. Along with the effects of peripheral auditory system declines on the auditory nerve, primary degeneration in the spiral ganglion also appears to contribute to central auditory system aging. These inner ear alterations often correlate with structural and functional changes throughout the central nervous system and may explain suprathreshold speech communication difficulties in older adults with hearing loss. Throughout this review we highlight potential methods and research directions, with the goal of advancing our understanding, prevention, diagnosis, and treatment of presbyacusis.
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Affiliation(s)
- Mark A Eckert
- Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA.
| | - Kelly C Harris
- Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA
| | - Hainan Lang
- Medical University of South Carolina, Department of Pathology and Laboratory Medicine, Charleston, SC 29425, USA
| | - Morag A Lewis
- King's College London, Wolfson Centre for Age-Related Diseases, London SE1 1UL, United Kingdom
| | - Richard A Schmiedt
- Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA
| | - Bradley A Schulte
- Medical University of South Carolina, Department of Pathology and Laboratory Medicine, Charleston, SC 29425, USA; Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA
| | - Karen P Steel
- King's College London, Wolfson Centre for Age-Related Diseases, London SE1 1UL, United Kingdom
| | - Kenneth I Vaden
- Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA
| | - Judy R Dubno
- Medical University of South Carolina, Department of Otolaryngology - Head and Neck Surgery, Charleston, SC 29425, USA; Medical University of South Carolina, Department of Pathology and Laboratory Medicine, Charleston, SC 29425, USA
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18
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Hu CJ, Lu YC, Yang TH, Chan YH, Tsai CY, Yu IS, Lin SW, Liu TC, Cheng YF, Wu CC, Hsu CJ. Toward the Pathogenicity of the SLC26A4 p.C565Y Variant Using a Genetically Driven Mouse Model. Int J Mol Sci 2021; 22:2789. [PMID: 33801843 PMCID: PMC8001573 DOI: 10.3390/ijms22062789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 11/19/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are globally a common cause of hearing impairment. In the past, cell lines and transgenic mice were widely used to investigate the pathogenicity associated with SLC26A4 variants. However, discrepancies in pathogenicity between humans and cell lines or transgenic mice were documented for some SLC26A4 variants. For instance, the p.C565Y variant, which was reported to be pathogenic in humans, did not exhibit functional pathogenic consequences in cell lines. To address the pathogenicity of p.C565Y, we used a genotype-based approach in which we generated knock-in mice that were heterozygous (Slc26a4+/C565Y), homozygous (Slc26a4C565Y/C565Y), and compound heterozygous (Slc26a4919-2A>G/C565Y) for this variant. Subsequent phenotypic characterization revealed that mice with these genotypes demonstrated normal auditory and vestibular functions, and normal inner-ear morphology and pendrin expression. These findings indicate that the p.C565Y variant is nonpathogenic for mice, and that a single p.C565Y allele is sufficient to maintain normal inner-ear physiology in mice. Our results highlight the differences in pathogenicity associated with certain SLC26A4 variants between transgenic mice and humans, which should be considered when interpreting the results of animal studies for SLC26A4-related deafness.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei 100, Taiwan; (I-S.Y.); (S.-W.L.)
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei 112, Taiwan
- Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Medical Genetics, National Taiwan University Hospital, Taipei 100, Taiwan
- Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan; (C.-J.H.); (Y.-C.L.); (T.-H.Y.); (Y.-H.C.); (C.-Y.T.); (T.-C.L.); (C.-J.H.)
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan
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19
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Simon F, Denoyelle F, Beraneck M. Interpreting pendred syndrome as a foetal hydrops: Clinical and animal model evidence. J Vestib Res 2021; 31:315-321. [PMID: 33579884 DOI: 10.3233/ves-200789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Menière disease (MD) and SLC26A4 related deafness (Pendred syndrome (PS) or DFNB4) are two different inner ear disorders which present with fluctuating and progressive hearing loss, which could be a direct consequence of endolymphatic hydrops. OBJECTIVE To present similarities between both pathologies and explore how the concept of hydrops may be applied to PS/DFNB4. METHODS Review of the literature on MD, PS/DFNB4 and mouse model of PS/DFNB4. RESULTS MD and PS/DFNB4 share a number of similarities such as fluctuating and progressive hearing loss, acute episodes with vertigo and tinnitus, MRI and histological evidence of endolymphatic hydrops (although with different underlying mechanisms). MD is usually diagnosed during the fourth decade of life whereas PS/DFNB4 is congenital. The PS/DFNB4 mouse models have shown that biallelic slc26a4 mutations lead to Na+ and water retention in the endolymph during the perinatal period, which in turn induces degeneration of the stria vascularis and hearing loss. Crossing clinical/imagery characteristics and animal models, evidence seems to support the hypothesis of PS being a foetal hydrops. CONCLUSIONS When understanding PS/DFNB4 as a developmental hydrops, treatments used in MD could be repositioned to PS.
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Affiliation(s)
- François Simon
- Université de Paris, INCC UMR 8002, CNRS, F-75006 Paris, France.,Université de Paris, Faculté de Médecine, F-75006 Paris, France.,Department of Paediatric Otolaryngology, AP-HP, Hôpital Necker-Enfants Malades, F-75015 Paris, France
| | - Françoise Denoyelle
- Université de Paris, Faculté de Médecine, F-75006 Paris, France.,Department of Paediatric Otolaryngology, AP-HP, Hôpital Necker-Enfants Malades, F-75015 Paris, France
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Eaton AF, Merkulova M, Brown D. The H +-ATPase (V-ATPase): from proton pump to signaling complex in health and disease. Am J Physiol Cell Physiol 2020; 320:C392-C414. [PMID: 33326313 PMCID: PMC8294626 DOI: 10.1152/ajpcell.00442.2020] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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21
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van der Valk WH, Steinhart MR, Zhang J, Koehler KR. Building inner ears: recent advances and future challenges for in vitro organoid systems. Cell Death Differ 2020; 28:24-34. [PMID: 33318601 PMCID: PMC7853146 DOI: 10.1038/s41418-020-00678-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
While inner ear disorders are common, our ability to intervene and recover their sensory function is limited. In vitro models of the inner ear, like the organoid system, could aid in identifying new regenerative drugs and gene therapies. Here, we provide a perspective on the status of in vitro inner ear models and guidance on how to improve their applicability in translational research. We highlight the generation of inner ear cell types from pluripotent stem cells as a particularly promising focus of research. Several exciting recent studies have shown how the developmental signaling cues of embryonic and fetal development can be mimicked to differentiate stem cells into “inner ear organoids” containing otic progenitor cells, hair cells, and neurons. However, current differentiation protocols and our knowledge of embryonic and fetal inner ear development in general, have a bias toward the sensory epithelia of the inner ear. We propose that a more holistic view is needed to better model the inner ear in vitro. Moving forward, attention should be made to the broader diversity of neuroglial and mesenchymal cell types of the inner ear, and how they interact in space or time during development. With improved control of epithelial, neuroglial, and mesenchymal cell fate specification, inner ear organoids would have the ability to truly recapitulate neurosensory function and dysfunction. We conclude by discussing how single-cell atlases of the developing inner ear and technical innovations will be critical tools to advance inner ear organoid platforms for future pre-clinical applications.
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Affiliation(s)
- Wouter H van der Valk
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, Netherlands.,Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Matthew R Steinhart
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jingyuan Zhang
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Plastic and Oral Surgery, Boston Children's Hospital, Boston, MA, 02115, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Karl R Koehler
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA. .,Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Department of Plastic and Oral Surgery, Boston Children's Hospital, Boston, MA, 02115, USA. .,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA. .,Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02115, USA.
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22
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Roesch S, Bernardinelli E, Wortmann S, Mayr JA, Bader I, Schweighofer-Zwink G, Rasp G, Dossena S. [Molecular and functional testing in case of hereditary hearing loss associated with the SLC26A4 gene]. Laryngorhinootologie 2020; 99:853-862. [PMID: 33307573 DOI: 10.1055/a-1190-4173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Due to development of molecular techniques at hand, the number of genomic sequence variants detected in patient investigations is rising constantly. The number of potentially involved genes in hereditary hearing loss is rising simultaneously.In this overview, current methods for diagnostic workup on a molecular and functional level for variants of the SLC26A4 gene are described. Based on the description of the physiological function of the resulting protein Pendrin, molecular investigations for interpretation of the function are explained. Based on these investigations, the potential clinical consequences of a variant may be predicted more precisely and simplify routine reporting of a proven genotype and a phenotype, at hand. Finally, subsequent clinical investigations necessary, such as perchlorate discharge test, as well as therapeutic options are discussed.
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Affiliation(s)
- Sebastian Roesch
- Universitätsklinik für Hals-Nasen-Ohrenkrankheiten der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Emanuele Bernardinelli
- Universitätsinstitut für Pharmakologie und Toxikologie der Paracelsus Medizinischen Privatuniversität Salzburg, Austria
| | - Saskia Wortmann
- Universitätsklinik für Kinder- und Jugendheilkunde der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Johannes A Mayr
- Universitätsklinik für Kinder- und Jugendheilkunde der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Ingrid Bader
- Division für klinische Genetik, Universitätsklinik für Kinder- und Jugendheilkunde der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Gregor Schweighofer-Zwink
- Universitätsklinik für Nuklearmedizin und Endokrinologie der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Gerd Rasp
- Universitätsklinik für Hals-Nasen-Ohrenkrankheiten der Paracelsus Medizinischen Privatuniversität Salzburg, SALK, Salzburg, Austria
| | - Silvia Dossena
- Universitätsinstitut für Pharmakologie und Toxikologie der Paracelsus Medizinischen Privatuniversität Salzburg, Austria
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Abstract
The delivery of therapies to the cochlea is notoriously challenging. It is an organ protected by a number of barriers that need to be overcome in the drug delivery process. Additionally, there are multiple sites of possible damage within the cochlea. Despite the many potential sites of damage, acquired otologic insults preferentially damage a single location. While progress has been made in techniques for inner ear drug delivery, the current techniques remain non-specific and our ability to deliver therapies in a cell-specific manner are limited. Fortunately, there are proteins specific to various cell-types within the cochlea (e.g., hair cells, spiral ganglion cells, stria vascularis) that function as biomarkers of site-specific damage. These protein biomarkers have potential to serve as targets for cell-specific inner ear drug delivery. In this manuscript, we review the concept of biomarkers and targeted- inner ear drug delivery and the well-characterized protein biomarkers within each of the locations of interest within the cochlea. Our review will focus on targeted drug delivery in the setting of acquired otologic insults (e.g., ototoxicity, noise-induce hearing loss). The goal is not to discuss therapies to treat acquired otologic insults, rather, to establish potential concepts of how to deliver therapies in a targeted, cell-specific manner. Based on our review, it is clear that future of inner ear drug delivery is a discipline filled with potential that will require collaborative efforts among clinicians and scientists to optimize treatment of otologic insults. Graphical Abstract ![]()
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24
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Gu S, Olszewski R, Taukulis I, Wei Z, Martin D, Morell RJ, Hoa M. Characterization of rare spindle and root cell transcriptional profiles in the stria vascularis of the adult mouse cochlea. Sci Rep 2020; 10:18100. [PMID: 33093630 PMCID: PMC7581811 DOI: 10.1038/s41598-020-75238-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/12/2020] [Indexed: 12/20/2022] Open
Abstract
The stria vascularis (SV) in the cochlea generates and maintains the endocochlear potential, thereby playing a pivotal role in normal hearing. Knowing transcriptional profiles and gene regulatory networks of SV cell types establishes a basis for studying the mechanism underlying SV-related hearing loss. While we have previously characterized the expression profiles of major SV cell types in the adult mouse, transcriptional profiles of rare SV cell types remained elusive due to the limitation of cell capture in single-cell RNA-Seq. The role of these rare cell types in the homeostatic function of the adult SV remain largely undefined. In this study, we performed single-nucleus RNA-Seq on the adult mouse SV in conjunction with sample preservation treatments during the isolation steps. We distinguish rare SV cell types, including spindle cells and root cells, from other cell types, and characterize their transcriptional profiles. Furthermore, we also identify and validate novel specific markers for these rare SV cell types. Finally, we identify homeostatic gene regulatory networks within spindle and root cells, establishing a basis for understanding the functional roles of these cells in hearing. These novel findings will provide new insights for future work in SV-related hearing loss and hearing fluctuation.
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Affiliation(s)
- Shoujun Gu
- Auditory Development and Restoration Program, National Institutes on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, 35 Convent Dr., Room 1F-226, Bethesda, MD, 20892, USA
| | - Rafal Olszewski
- Auditory Development and Restoration Program, National Institutes on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, 35 Convent Dr., Room 1F-226, Bethesda, MD, 20892, USA
| | - Ian Taukulis
- Auditory Development and Restoration Program, National Institutes on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, 35 Convent Dr., Room 1F-226, Bethesda, MD, 20892, USA
| | - Zheng Wei
- Biomedical Research Informatics Office, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, 20892, USA
| | - Daniel Martin
- Biomedical Research Informatics Office, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, 20892, USA
| | - Robert J Morell
- Computational Biology and Genomics Core, National Institutes on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institutes on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, 35 Convent Dr., Room 1F-226, Bethesda, MD, 20892, USA.
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25
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Tsukada K, Usami SI. Detailed MR imaging assessment of endolymphatic hydrops in patients with SLC26A4 mutations. Auris Nasus Larynx 2020; 47:958-964. [PMID: 32536503 DOI: 10.1016/j.anl.2020.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/02/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Mutations in SLC26A4 represent the second most common mutations in deafness patients. The majority of patients with SLC26A4 mutations have a large vestibular aqueduct (LVA). Recently, some reports showed the presence of endolymphatic hydrops (ELH) in patients with LVA on the basis of high-resolution enhanced 3T-MRI. However, detailed evaluation has not been performed. We provide the first report on ELH in LVA patients with biallelic SLC26A4 mutations. In this study, we focused on 1) the findings of ELH in LVA patients with biallelic SLC26A4 mutations, and 2) the findings of the endolymphatic duct (ED) and endolymphatic sac (ES) by using two different gadodimide (Gd) enhancement methods. SUBJECTS AND METHODS Five patients with SLC26A4 mutations underwent enhanced 3T-MRI using the intratympanic (IT) or intravenous (IV) injection of Gd for the diagnosis ELH. RESULTS All of the patients had ELH in at least one ear. ELH was identified in the vestibule (8/10 ears) as well as in the cochlea (7/10 ears). With regard to the ED and ES, all ears for which MRI was performed with an IT injection of Gd had black areas in the ES or VA or both; however, all of the ears receiving an IV injection had no black areas and were well enhanced. CONCLUSIONS A majority of the patients had severe ELH in the cochleo-vestibular endolymph, with two different patterns observed in the MRI findings of the ED and ES.
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Affiliation(s)
- Keita Tsukada
- Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto City, 390-8621, Japan
| | - Shin-Ichi Usami
- Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto City, 390-8621, Japan.
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26
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Wen C, Wang S, Zhao X, Wang X, Wang X, Cheng X, Huang L. Mutation analysis of the SLC26A4 gene in three Chinese families. Biosci Trends 2019; 13:441-447. [PMID: 31656273 DOI: 10.5582/bst.2019.01282] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In order to investigate the genetic causes of hearing loss in a Chinese proband (in Family A) with enlarged vestibular aqueduct (EVA) and to investigate the genotype of two Chinese probands with SLC26A4 singe-allelic mutation and normal hearing (in Families B and C, respectively), the three probands and their parents were clinically and genetically evaluated. Twenty exons and flanking splice sites of the SLC26A4 gene were screened for pathogenic mutations via amplification with PCR and bidirectional sequencing. As controls, a group of 400 healthy newborns from the same ethnic background underwent SLC26A4 gene screening using the same method. The three probands all harbored two mutations in the SLC26A4 gene in the form of compound heterozygosity. The genotypes of mutations in Families A, B, and C are c.1211C>A/c.919-2A>G, c.1729G>A/c.919-2A>G, and c.1286C>A/c.919-2A>G, respectively. The missense mutations c.1211C>A (p.T430Q) in exon 10 and c.1729G>A (p.V577I) in exon 16 are both reported for the first time and were absent in 400 healthy newborns. c.1211C>A has Glutamine (Gln) at amino acid 430 instead of Threonine (Thr), and c.1729G>A has Isoleucine (Ile) at amino acid 577 instead of Valine (Val). c.1286C>A, a mutation previously reported in DVD and HGMD, was associated with Mondini deformity, but a proband with the c.1286C>A mutation in this study was normal. This study has demonstrated that the novel missense mutation c.1211C>A in compound heterozygosity with c.919-2A>G in the SLC26A4 gene is likely to be the cause of deafness in Family A. A novel variant, c.1729G>A, was identified and is likely benign. The pathogenicity of the c.1286C>A mutation warrants more in-depth study. These findings will broaden the spectrum of known SLC26A4 mutations in the Chinese population, providing more information for genetic counseling and diagnosis of hearing loss with EVA.
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Affiliation(s)
- Cheng Wen
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Shijie Wang
- No. 731 Hospital of China Aerospace Science and Industry Corp, Beijing, China
| | - Xuelei Zhao
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xianlei Wang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xueyao Wang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Xiaohua Cheng
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
| | - Lihui Huang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Beijing, China
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27
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Mey K, Muhamad AA, Tranebjaerg L, Rendtorff ND, Rasmussen SH, Bille M, Cayé-Thomasen P. Association of SLC26A4 mutations, morphology, and hearing in pendred syndrome and NSEVA. Laryngoscope 2019; 129:2574-2579. [PMID: 31633822 DOI: 10.1002/lary.27319] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/07/2018] [Accepted: 05/03/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To investigate the relations of monoallelic (M1), biallelic (M2), or the absence of mutations (M0) in SLC26A4 to inner ear morphology and hearing levels in individuals with Pendred syndrome (PS) or nonsyndromic enlarged vestibular aqueduct (NSEVA) associated with hearing loss. METHODS In a cohort of 139 PS/NSEVA individuals, 115 persons from 95 unrelated families had full genetic sequencing of SLC26A4, and 113 had retrievable images for re-assessment of inner ear morphology. The association between the number of mutant alleles in SLC26A4, inner ear morphology (including endolymphatic sac size and protein content on magnetic resonance imaging), and hearing level (pure tone average) was explored. RESULTS Biallelic SLC26A4 mutations (M2) occurred in three-quarters of the cohort and was invariably associated with poor hearing; in 87%, it was associated with incomplete partition type II of the cochlea as well as enlarged endolymphatic sac and vestibular aqueduct. M1 or M0 individuals exhibited a greater variability in inner ear morphology. Endolymphatic sac size and presence of "high-protein" sac contents were significantly higher in M2 individuals compared to M1 and M0 individuals. CONCLUSION The number of SLC26A4 mutations is associated with severity and variability of inner ear morphology and hearing level in individuals with PS or NSEVA. M2 individuals have poorer hearing and present largely incomplete partition type II of the cochleas with enlarged endolymphatic sacs, whereas individuals with M1 and no detectable SLC26A4 mutations have less severe hearing loss and more diverse inner ear morphology. LEVEL OF EVIDENCE 4. Laryngoscope, 129:2574-2579, 2019.
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Affiliation(s)
- Kristianna Mey
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology Rigshospitalet/Gentofte, Hellerup
| | | | - Lisbeth Tranebjaerg
- the Department of Clinical Genetics, Rigshospitalet/The Kennedy Center.,the Institute of Clinical Medicine
| | - Nanna D Rendtorff
- the Department of Clinical Genetics, Rigshospitalet/The Kennedy Center
| | | | - Michael Bille
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology Rigshospitalet/Gentofte, Hellerup
| | - Per Cayé-Thomasen
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology Rigshospitalet/Gentofte, Hellerup.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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28
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Touré A. Importance of SLC26 Transmembrane Anion Exchangers in Sperm Post-testicular Maturation and Fertilization Potential. Front Cell Dev Biol 2019; 7:230. [PMID: 31681763 PMCID: PMC6813192 DOI: 10.3389/fcell.2019.00230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
In mammals, sperm cells produced within the testis are structurally differentiated but remain immotile and are unable to fertilize the oocyte unless they undergo a series of maturation events during their transit in the male and female genital tracts. This post-testicular functional maturation is known to rely on the micro-environment of both male and female genital tracts, and is tightly controlled by the pH of their luminal milieus. In particular, within the epididymis, the establishment of a low bicarbonate (HCO3–) concentration contributes to luminal acidification, which is necessary for sperm maturation and subsequent storage in a quiescent state. Following ejaculation, sperm is exposed to the basic pH of the female genital tract and bicarbonate (HCO3–), calcium (Ca2+), and chloride (Cl–) influxes induce biochemical and electrophysiological changes to the sperm cells (cytoplasmic alkalinization, increased cAMP concentration, and protein phosphorylation cascades), which are indispensable for the acquisition of fertilization potential, a process called capacitation. Solute carrier 26 (SLC26) members are conserved membranous proteins that mediate the transport of various anions across the plasma membrane of epithelial cells and constitute important regulators of pH and HCO3– concentration. Most SLC26 members were shown to physically interact and cooperate with the cystic fibrosis transmembrane conductance regulator channel (CFTR) in various epithelia, mainly by stimulating its Cl– channel activity. Among SLC26 members, the function of SLC26A3, A6, and A8 were particularly investigated in the male genital tract and the sperm cells. In this review, we will focus on SLC26s contributions to ionic- and pH-dependent processes during sperm post-testicular maturation. We will specify the current knowledge regarding their functions, based on data from the literature generated by means of in vitro and in vivo studies in knock-out mouse models together with genetic studies of infertile patients. We will also discuss the limits of those studies, the current research gaps and identify some key points for potential developments in this field.
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Affiliation(s)
- Aminata Touré
- INSERM U1016, Centre National de la Recherche Scientifique, UMR 8104, Institut Cochin, Université de Paris, Paris, France
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29
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Generation of a human iPS cell line (CGMH.SLC26A4919-2) from a Pendred syndrome patient carrying SLC26A4 c.919-2A>G splice-site mutation. Stem Cell Res 2019; 40:101524. [PMID: 31415960 DOI: 10.1016/j.scr.2019.101524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 11/20/2022] Open
Abstract
SLC26A4 is the second most frequent gene implicated in congenital hearing loss after GJB2 mutations. Here, we report the generation of induced pluripotent stem cells (iPSCs), from a patient who was carrying a homozygous c.919-2A>G variant in the SLC26A4 gene. This is the most common variant of SLC26A4 gene in the Chinese population and the second most prevalent one in other Asian countries. The established patient-derived iPSC displayed all the features of pluripotent stem cell markers and had the ability to differentiate into all of the three germ layers and possessed a normal karyotype.
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30
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Wen Z, Zhu H, Li Z, Zhang S, Zhang A, Zhang T, Fu X, Sun D, Zhang J, Gao J. A knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation. Biochem Biophys Res Commun 2019; 515:359-365. [PMID: 31155292 DOI: 10.1016/j.bbrc.2019.05.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 05/25/2019] [Indexed: 11/25/2022]
Abstract
SLC26A4 gene mutations lead to Pendred syndrome and non-syndromic hearing loss (DFNB4). The mouse model is well used to study the pathology of Pendred syndrome, however, mice with different Slc26a4 mutations exhibit different phenotypes, and these mice have severe deafness and inner ear malformations that are not imitated less severely Human phenotype. In this study, we generated a knock-in mouse model of Pendred syndrome with Slc26a4 L236P mutation to mimic the most common mutation found in human. Some L236P mice were observed to have significant vestibular dysfunction including torticollis and circling, the giant otoconia and destruction of the otoconial membrane was observed in L236P mice. Unlike other profoundly deafness in Slc26a4 mouse model, L236P mice present mild to profound hearing loss, consistent with the hearing threshold, inner ear hair cells also lost from slight to significant. Together, these data demonstrate that the L236P mouse phenotype is more similar to the human phenotype and should be used as a tool for further research into the human Pendred syndrome.
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Affiliation(s)
- Zongzhuang Wen
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Haixia Zhu
- State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhenzu Li
- Department of Bioengineering, Shandong Polytechnic, Jinan, Shandong, China
| | - Sen Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Aizhen Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Tingting Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Xiaolong Fu
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China
| | - Daqing Sun
- Department of Paediatric Surgery, Tianjin Medical University General Hospital, Tianjin, China.
| | - Jian Zhang
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China.
| | - Jiangang Gao
- Institute of Developmental Biology, School of Life Science, Shandong University, Jinan, Shandong, China.
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31
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Zhao X, Cheng X, Huang L, Wang X, Wen C, Wang X. Novel compound heterozygous mutations in SLC26A4 gene in a Chinese family with enlarged vestibular aqueduct. Biosci Trends 2018; 12:502-506. [PMID: 30473558 DOI: 10.5582/bst.2018.01260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In order to investigate the genetic causes of hearing loss in a Chinese proband with nonsyndromic hearing loss and enlarged vestibular aqueduct (EVA), we conducted clinical and genetic evaluations in a deaf proband and her parents with normal hearing. 20 exons and flanking splice sites of the SLC26A4 gene were screened for pathogenic mutations by PCR amplification and bidirectional sequencing. As a control, a group of 400 healthy newborns from the same ethnic background were subjected to SLC26A4 gene screening using the same method. The proband harbored two mutations in the SLC26A4 gene in the form of compound heterozygosity. She was found to be heterozygous for a novel mutation c.574delC (p.Leu192Ter) in exon 5 and for the known mutation c.919-2A>G(c.IVS7-2A>G). Her mother was a heterozygous carrier of the c.919-2A>G mutation, and her father was a heterozygous carrier of the c.574delC and therefore co-segregated with the genetic disease. The c.574delC mutation was absent in 400 healthy newborns. The frameshift mutation causes the leucine (Leu) at amino acid position 192 to become a termination codon, leading to termination of protein sequence coding. This study demonstrates that the novel frameshift mutation c.574delC (p.Leu192Ter) in compound heterozygosity with c.919-2A>G in the SLC26A4 gene is the main cause of deafness in a family. Our study will expand the spectrum of known SLC26A4 mutations in the Chinese population, providing more information on genetic counseling, and diagnosis in hearing loss with EVA.
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Affiliation(s)
- Xuelei Zhao
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
| | - Xiaohua Cheng
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
| | - Lihui Huang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
| | - Xianlei Wang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
| | - Cheng Wen
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
| | - Xueyao Wang
- Beijing Tongren Hospital, Capital Medical University; Beijing Institute of Otolaryngology; Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education
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Ji M, Xiao L, Xu L, Huang S, Zhang D. How pH is regulated during amelogenesis in dental fluorosis. Exp Ther Med 2018; 16:3759-3765. [PMID: 30402142 DOI: 10.3892/etm.2018.6728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/01/2017] [Indexed: 12/14/2022] Open
Abstract
Amelogenesis is a complicated process that concerns the interaction between growing hydroxyapatite crystals and extracellular proteins, which requires the tight regulation of pH. In dental fluorosis, the balance of pH regulation is broken, leading to abnormal mineralization. The current review focuses on the electrolyte transport processes associated with pH homeostasis, particularly regarding the changes in ion transporters that occur during amelogenesis, following exposure to excessive fluoride. Furthermore, the possible mechanism of fluorosis is discussed on the basis of acid hypothesis. There are two main methods by which F- accelerates crystal formation in ameloblasts. Firstly, it induces the release of protons, lowering the pH of the cell microenvironment. The decreased pH stimulates the upregulation of ion transporters, which attenuates further declines in the pH. Secondly, F- triggers an unknown signaling pathway, causing changes in the transcription of ion transporters and upregulating the expression of bicarbonate transporters. This results in the release of a large amount of bicarbonate from ameloblasts, which may neutralize the pH to form a microenvironment that favors crystal nucleation. The decreased pH stimulates the diffusion of F- into the cytoplasm of amelobalsts along the concentration gradient formed by the release of protons. The retention of F- causes a series of pathological changes, including oxidative and endoplasmic reticulum stress. If the buffering capacity of ameloblasts facing F- toxicity holds, normal mineralization occurs; however, if F- levels are high enough to overwhelm the buffering capacity of ameloblasts, abnormal mineralization occurs, leading to dental fluorosis.
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Affiliation(s)
- Mei Ji
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Lili Xiao
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Le Xu
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shengyun Huang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dongsheng Zhang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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Liang Y, Peng Q, Wang K, Zhu P, Wu C, Rao C, Chang J, Li S, Lu X. A novel mutation in the SLC26A4 gene in a Chinese family with non-syndromic hearing loss and enlarged vestibular aqueduct. Int J Pediatr Otorhinolaryngol 2018; 107:97-100. [PMID: 29501320 DOI: 10.1016/j.ijporl.2018.01.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/04/2017] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To identity the genetic causes of hearing loss in a Han Chinese family with enlarged vestibular aqueduct syndrome. METHODS Multiplex PCR technology combined with Ion Torrent™ next-generation sequencing technology was used to search for pathogenic mutations. A group of 1500 ethnically-matched normal hearing subjects screened for mutations in deafness-related genes using the same method in previously studied were included as a control. RESULTS The proband and his little sister suffered from typical features of sensorineural hearing loss with enlarged vestibular aqueduct (EVA). Both subjects harbored two compound heterozygous mutations in the SLC26A4 gene. A novel mutation named c.2110 G > C (p.Glu704Gln) in exon 19 and another previously reported mutation c.1673 A > T (p.Asn558Ile) were identified. These mutations were carried in the heterozygous state by the parents and therefore co-segregated with the genetic disease. The c.2110 G > C (p.Glu704Gln) mutation was absent in 1500 healthy newborns. Protein alignment indicated high evolutionary conservation of the p.E704 residue, and this mutation was predicted by online tools to be damaging and deleterious. CONCLUSION This study demonstrates that the novel mutation c.2110 G > C (p.Glu704Gln) in compound heterozygosity with c.1673 A > T (p.Asn558Ile) in the SLC26A4 gene corresponds to the EVA in this family. Our study will provide a foundation for elucidating the SLC26A4-related mechanisms of hearing loss.
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Affiliation(s)
- Yuan Liang
- Department of Neurology, Dongguan Children's Hospital, Dongguan, Guangdong, China; Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China
| | - Qi Peng
- Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China
| | - Kangwei Wang
- Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China
| | - Pengyuan Zhu
- CapitalBio Genomics Co., Ltd, Dongguan, Guangdong, China
| | - Chunqiu Wu
- CapitalBio Genomics Co., Ltd, Dongguan, Guangdong, China
| | - Chunbao Rao
- Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China
| | - Jiang Chang
- Department of Otorhinolaryngology, Dongguan Children's Hospital, Dongguan, Guangdong, China
| | - Siping Li
- Medical Laboratory, Dongguan Children's Hospital, Dongguan, Guangdong, China.
| | - Xiaomei Lu
- Department of Medical and Molecular Genetics, Dongguan Institute of Pediatrics, Dongguan, Guangdong, China.
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Luo J, Bai X, Zhang F, Xiao Y, Gu L, Han Y, Fan Z, Li J, Xu L, Wang H. Prevalence of Mutations in Deafness-Causing Genes in Cochlear Implanted Patients with Profound Nonsyndromic Sensorineural Hearing Loss in Shandong Province, China. Ann Hum Genet 2017; 81:258-266. [PMID: 28786104 DOI: 10.1111/ahg.12207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 11/27/2022]
Abstract
The mutations of GJB2, SLC26A4, and mtDNA12SrRNA are the most common inherited causes of nonsyndromic sensorineural hearing loss (NSHL) in China, yet previous genetic screenings were mainly carried on patients with moderate-to-profound impairment. We aimed to detect the mutation frequencies in NSHL population within a more specified range of severity. Patients with profound NSHL who had undergone cochlear implantation in the Shandong Provincial Hospital (Shandong, China) were recruited. The majority (n = 472) were between 0.7 and 6 years old, and the remaining (n = 63) were between 6 and 70 years old. In total, 115 mutation alleles of the three genes were screened with SNP scan assay. Of the patients, 19.44% (104/535) were found to have GJB2 mutations, and the most common allele was c.235delC, followed by c.299_300delAT and c.109G>A. SLC26A4 mutations were detected in 13.46% patients (72/535), and the most common allele was c.919-2A>G (IVS7-2A>G), followed by c.1174A>T and c.2168A>G. Seven patients (1.31%) carried mutations in mtDNA12SrRNA, with the alleles of m.1555A>G and m.1494C>T. We found the allele frequency of c.109G>A (GJB2) was relatively lower in the profound NSHL population in comparison to the moderate-to-profound ones, and the c.1174A>T (SLC26A4) relatively higher. It suggests those mutations may be connected with the degree of deafness, which needs more observations and analyses to support.
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Affiliation(s)
- Jianfen Luo
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Xiaohui Bai
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Fengguo Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Yun Xiao
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Lintao Gu
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China
| | - Yuechen Han
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Zhaomin Fan
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Jianfeng Li
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Lei Xu
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
| | - Haibo Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China.,Shandong Provincial Key Laboratory of Otology, Shandong, China
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Runggaldier D, Pradas LG, Neckel PH, Mack AF, Hirt B, Gleiser C. Claudin expression in the rat endolymphatic duct and sac - first insights into regulation of the paracellular barrier by vasopressin. Sci Rep 2017; 7:45482. [PMID: 28374851 PMCID: PMC5379655 DOI: 10.1038/srep45482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/28/2017] [Indexed: 12/13/2022] Open
Abstract
Hearing and balance functions of the inner ear rely on the homeostasis of the endolymphatic fluid. When disturbed, pathologic endolymphatic hydrops evolves as observed in Menière’s disease. The molecular basis of inner ear fluid regulation across the endolymphatic epithelium is largely unknown. In this study we identified the specific expression of the tight junction (TJ) molecules Claudin 3, 4, 6, 7, 8, 10, and 16 in epithelial preparations of the rat inner ear endolymphatic duct (ED) and endolymphatic sac (ES) by high-throughput qPCR and immunofluorescence confocal microscopy. Further we showed that Claudin 4 in the ES is a target of arginine-vasopressin (AVP), a hormone elevated in Menière’s disease. Moreover, our transmission-electron microscopy (TEM) analysis revealed that the TJs of the ED were shallow and shorter compared to the TJ of the ES indicating facilitation of a paracellular fluid transport across the ED epithelium. The significant differences in the subcellular localization of the barrier-forming protein Claudin 3 between the ED and ES epithelium further support the TEM observations. Our results indicate a high relevance of Claudin 3 and Claudin 4 as important paracellular barrier molecules in the ED and ES epithelium with potential involvement in the pathophysiology of Menière’s disease.
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Affiliation(s)
- Daniel Runggaldier
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Lidia Garcia Pradas
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Peter H Neckel
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Andreas F Mack
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Bernhard Hirt
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
| | - Corinna Gleiser
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen, Germany
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A novel missense mutation in the SLC26A4 gene causes nonsyndromic hearing loss and enlarged vestibular aqueduct. Int J Pediatr Otorhinolaryngol 2017; 95:104-108. [PMID: 28576516 DOI: 10.1016/j.ijporl.2017.02.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 02/10/2017] [Accepted: 02/12/2017] [Indexed: 11/20/2022]
Abstract
OBJECTIVES We aimed to investigate the genetic causes of hearing loss in a Chinese proband with nonsyndromic hearing loss and enlarged vestibular aqueduct syndrome. METHODS We conducted clinical and genetic evaluations in a deaf proband and his normal-hearing parents. Multiplex PCR technology combined with Ion Torrent™ next-generation sequencing technology was used to detect the pathogenic mutations. As a control, a group of 1500 previously studied healthy newborns from the same ethnic background were subjected to deafness gene screening using the same method as in our previous study. RESULTS The proband harbored two mutations in the SLC26A4 gene in the form of compound heterozygosity. He was found to be heterozygous for a novel mutation named c.1742 G > T (p.Arg581Met) in exon 13 and for the known mutation c.589 G > A (p.Gly197Arg). These variants were carried in the heterozygous state by the parents and therefore co-segregated with the genetic disease. The c.1742 G > T (p.Arg581Met) mutation was absent in 1500 healthy newborns. Protein alignment indicated high evolutionary conservation of the p.R581 residue, and this mutation was predicted by PolyPhen-2 and other online tools to be damaging. CONCLUSION This study demonstrates that the novel mutation c.1742 G > T (p.Arg581Met) in compound heterozygosity with c.589 G > A in the SLC26A4 gene is the main cause of deafness in a family clinically diagnosed with enlarged vestibular aqueduct (EVA). Our study will provide a basic foundation for further investigations to elucidate the SLC26A4-related mechanisms of hearing loss.
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Wang M, Zhang F, Xu L, Xiao Y, Li J, Fan Z, Sun Q, Bai X, Wang H. Novel compound heterozygous mutations in SLC26A4 gene in a Chinese Han family with enlarged vestibular aqueduct. Int J Pediatr Otorhinolaryngol 2016; 90:170-174. [PMID: 27729126 DOI: 10.1016/j.ijporl.2016.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/13/2016] [Accepted: 09/15/2016] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To identify the disease-related SLC26A4 mutants in a Chinese Han pedigree associated with Enlarged vestibular aqueduct (EVA). METHODS EVA diagnosis was based on the family history, clinical examinations, systematically audiometric evaluations, high-resolution computed tomography (HRCT) of the temporal bone, and magnetic resonance imaging (MRI) of inner ear. Sanger sequencing and mutation analysis of the SLC26A4 gene were performed in all members of this family to identify the disease-related SLC26A4 mutants. Mutations in the SLC26A4 gene were compared with 200 ethnically matched control persons to exclude common polymorphism. RESULTS All members in this family were negative for systemic and thyroid diseases. There were three subjects (I-2, II-2 and II-3) with bilateral sensorineural deafness since childhood. Temporal bone HRCT scans and inner ear MRI showed bilateral enlarged vestibular aqueduct with Mondini malformation in II-2 and II-3. A novel SLC26A4 splice-site mutation c.1001 + 5G > C was identified in compound heterozygosity with the mutation c.919-2A > G in the proband and in II-2. This novel compound heterozygote of two splice site mutations was not found in 200 normal hearing Chinese Han controls. CONCLUSIONS A novel splice site mutation of c.1001 + 5G > C was identified, and the novel compound heterozygote of two splice site mutations, c.1001 + 5G > C and c.919-2A > G, in the SLC26A4 gene has been linked to hearing impairment in EVA patients.
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Affiliation(s)
- Mingming Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Fengguo Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Lei Xu
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Yun Xiao
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Jianfeng Li
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Zhaomin Fan
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China
| | - Qian Sun
- Emory University, Human Genetics Department, Atlanta, GA, USA
| | - Xiaohui Bai
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China.
| | - Haibo Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; Shandong Provincial Key Laboratories of Otology, Jinan, China.
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Ion transport its regulation in the endolymphatic sac: suggestions for clinical aspects of Meniere's disease. Eur Arch Otorhinolaryngol 2016; 274:1813-1820. [PMID: 27804084 PMCID: PMC5340852 DOI: 10.1007/s00405-016-4362-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 10/26/2016] [Indexed: 01/22/2023]
Abstract
Ion transport and its regulation in the endolymphatic sac (ES) are reviewed on the basis of recent lines of evidence. The morphological and physiological findings demonstrate that epithelial cells in the intermediate portion of the ES are more functional in ion transport than those in the other portions. Several ion channels, ion transporters, ion exchangers, and so on have been reported to be present in epithelial cells of ES intermediate portion. An imaging study has shown that mitochondria-rich cells in the ES intermediate portion have a higher activity of Na+, K+-ATPase and a higher Na+ permeability than other type of cells, implying that molecules related to Na+ transport, such as epithelial sodium channel (ENaC), Na+–K+–2Cl− cotransporter 2 (NKCC2) and thiazide-sensitive Na+–Cl− cotransporter (NCC), may be present in mitochondria-rich cells. Accumulated lines of evidence suggests that Na+ transport is most important in the ES, and that mitochondria-rich cells play crucial roles in Na+ transport in the ES. Several lines of evidence support the hypothesis that aldosterone may regulate Na+ transport in ES, resulting in endolymph volume regulation. The presence of molecules related to acid/base transport, such as H+-ATPase, Na+–H+ exchanger (NHE), pendrin (SLC26A4), Cl−–HCO3− exchanger (SLC4A2), and carbonic anhydrase in ES epithelial cells, suggests that acid/base transport is another important one in the ES. Recent basic and clinical studies suggest that aldosterone may be involved in the effect of salt-reduced diet treatment in Meniere’s disease.
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Mittal R, Aranke M, Debs LH, Nguyen D, Patel AP, Grati M, Mittal J, Yan D, Chapagain P, Eshraghi AA, Liu XZ. Indispensable Role of Ion Channels and Transporters in the Auditory System. J Cell Physiol 2016; 232:743-758. [DOI: 10.1002/jcp.25631] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 09/30/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Mayank Aranke
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Luca H. Debs
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Desiree Nguyen
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Amit P. Patel
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - M'hamed Grati
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Jeenu Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Denise Yan
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Prem Chapagain
- Department of Physics; Florida International University; Miami Florida
- Biomolecular Science Institute; Florida International University; Miami Florida
| | - Adrien A. Eshraghi
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Xue Zhong Liu
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
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Nin F, Yoshida T, Sawamura S, Ogata G, Ota T, Higuchi T, Murakami S, Doi K, Kurachi Y, Hibino H. The unique electrical properties in an extracellular fluid of the mammalian cochlea; their functional roles, homeostatic processes, and pathological significance. Pflugers Arch 2016; 468:1637-49. [PMID: 27568193 PMCID: PMC5026722 DOI: 10.1007/s00424-016-1871-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 12/13/2022]
Abstract
The cochlea of the mammalian inner ear contains an endolymph that exhibits an endocochlear potential (EP) of +80 mV with a [K(+)] of 150 mM. This unusual extracellular solution is maintained by the cochlear lateral wall, a double-layered epithelial-like tissue. Acoustic stimuli allow endolymphatic K(+) to enter sensory hair cells and excite them. The positive EP accelerates this K(+) influx, thereby sensitizing hearing. K(+) exits from hair cells and circulates back to the lateral wall, which unidirectionally transports K(+) to the endolymph. In vivo electrophysiological assays demonstrated that the EP stems primarily from two K(+) diffusion potentials yielded by [K(+)] gradients between intracellular and extracellular compartments in the lateral wall. Such gradients seem to be controlled by ion channels and transporters expressed in particular membrane domains of the two layers. Analyses of human deafness genes and genetically modified mice suggested the contribution of these channels and transporters to EP and hearing. A computational model, which reconstitutes unidirectional K(+) transport by incorporating channels and transporters in the lateral wall and connects this transport to hair cell transcellular K(+) fluxes, simulates the circulation current flowing between the endolymph and the perilymph. In this model, modulation of the circulation current profile accounts for the processes leading to EP loss under pathological conditions. This article not only summarizes the unique physiological and molecular mechanisms underlying homeostasis of the EP and their pathological relevance but also describes the interplay between EP and circulation current.
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Affiliation(s)
- Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Takamasa Yoshida
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Seishiro Sawamura
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
| | - Takeru Ota
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Shingo Murakami
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Osaka, 565-0871, Japan
- Center for Advanced Medical Engineering and Informatics, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Department of Physiology, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, 589-8511, Japan
| | - Yoshihisa Kurachi
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Osaka, 565-0871, Japan
- Center for Advanced Medical Engineering and Informatics, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan.
- AMED-CREST, AMED, Niigata, Japan.
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Suzuki M, Kotani R. Effects of perilymphatic pressure, sodium nitroprusside, and bupivacaine on cochlear fluid pH of guinea pigs. Acta Otolaryngol 2016; 135:1219-24. [PMID: 26327567 DOI: 10.3109/00016489.2015.1077392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS Hydrostatic positive pressure and vasoconstrictor acidified the cochlear fluids, whereas the vasodilator made the fluids alkaline. CBF might play a role in regulating cochlea fluid pH. OBJECTIVES Cochlea fluid pH is highly dependent on the HCO3(-)/CO2 buffer system. Cochlear blood flow (CBF) supplies O2 and removes CO2. It is speculated that cochlear blood flow changes might affect the balance of the HCO3(-)/CO2 buffer system in the cochlea. It is known that the elevation of inner ear pressure decreases the CBF, and local application of vasodilating or vasoconstricting agents directly to the cochlea changes the CBF. The purpose of this study was to elucidate the effect of positive hydrostatic inner ear pressure and application of a vasodilator and vasoconstrictor of cochlear vessels on the pH of the endolymph and perilymph. METHODS The authors performed animal physiological experiments on 30 guinea pigs. Hydrostatic positive pressure was infused through a glass capillary tube inserted into the scala tympani of the basal turn. The vasodilator, nitric oxide donor (sodium nitroprusside; SNP), and the vasoconstrictor, bupivacaine, were placed topically onto the round window of the guinea pig cochlea. Endolymph pH (pHe) and endocochlear potential (EP) were monitored by double-barreled ion-selective microelectrodes in the second turn of the guinea pig cochlea. During the topical application study, scala vestibuli perilymph pH (pHv) was also measured simultaneously in the second turn. RESULTS The application of hydrostatic positive pressure caused a decrease in pHe and EP. Positive perilymphatic pressure caused the endolymph to become acidic pressure-dependently. Application of 3.0% SNP evoked an increase in both the pHe and pHv, following by a gradual recovery to baseline levels. On the other hand, 0.5% bupivacaine caused a decrease in both the pHe and pHv. The EP during topical application showed slight, non-significant changes.
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Affiliation(s)
- Masaaki Suzuki
- a Department of Otolaryngology, Teikyo University Chiba Medical Center , Chiba, Japan
| | - Ryosuke Kotani
- a Department of Otolaryngology, Teikyo University Chiba Medical Center , Chiba, Japan
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Ajij M, Shambhavi, Patra B, Singh A, Kapoor S. Pendred Syndrome in a Newborn with Neck Swelling: A Case Report. J Trop Pediatr 2016; 62:338-40. [PMID: 26936928 DOI: 10.1093/tropej/fmw002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Pendred syndrome is a rare autosomal recessive condition, characterized by functional impairment of thyroid gland and sensorineural hearing loss. The syndrome presents in patients with homozygous or compound heterozygous mutation. The presentation in the form of neck mass in a newborn is rare. CASE CHARACTERISTICS A 1 month old baby presented to us with neck mass, which was found to be an enlarged thyroid gland. Thyroid function tests were consistent with hypothyroidism. Further evaluation revealed moderate sensorineural hearing loss; genetic analysis showed that baby was homozygous for the known mutations causing the disease. INTERVENTION Thyroid hormone replacement and hearing habilitation were done. Follow up showed regression of the neck mass and normalization of thyroid function tests. Genetic counseling of the family was done. MESSAGE Identification of the exact cause of congenital hypothyroidism can prevent grave consequences later on for the patient as well as for the family.
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Affiliation(s)
- Mohemmed Ajij
- Department of Pediatrics, SMS Medical College and JK Lon Hospital, Jaipur, Rajasthan, 302004 India
| | - Shambhavi
- Department of Pediatrics, SMS Medical College and JK Lon Hospital, Jaipur, Rajasthan, 302004 India
| | - Bijoy Patra
- Department of Pediatrics, Lady Hardinge Medical College, New Delhi, 302004 India
| | - Ankur Singh
- Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, 302004 India
| | - Seema Kapoor
- Department of Pediatrics, Genetic Unit, MAMC, New Delhi, 302004 India
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The unique ion permeability profile of cochlear fibrocytes and its contribution to establishing their positive resting membrane potential. Pflugers Arch 2016; 468:1609-19. [PMID: 27344659 DOI: 10.1007/s00424-016-1853-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/30/2016] [Accepted: 06/14/2016] [Indexed: 11/27/2022]
Abstract
Eukaryotic cells exhibit negative resting membrane potential (RMP) owing to the high K(+) permeability of the plasma membrane and the asymmetric [K(+)] between the extracellular and intracellular compartments. However, cochlear fibrocytes, which comprise the basolateral surface of a multilayer epithelial-like tissue, exhibit a RMP of +5 to +12 mV in vivo. This positive RMP is critical for the formation of an endocochlear potential (EP) of +80 mV in a K(+)-rich extracellular fluid, endolymph. The epithelial-like tissue bathes fibrocytes in a regular extracellular fluid, perilymph, and apically faces the endolymph. The EP, which is essential for hearing, represents the potential difference across the tissue. Using in vivo electrophysiological approaches, we describe a potential mechanism underlying the unusual RMP of guinea pig fibrocytes. The RMP was +9.0 ± 3.7 mV when fibrocytes were exposed to an artificial control perilymph (n = 28 cochleae). Perilymphatic perfusion of a solution containing low [Na(+)] (1 mM) markedly hyperpolarized the RMP to -31.1 ± 11.2 mV (n = 10; p < 0.0001 versus the control, Tukey-Kramer test after one-way ANOVA). Accordingly, the EP decreased. Little change in RMP was observed when the cells were treated with a high [K(+)] of 30 mM (+10.4 ± 2.3 mV; n = 7; p = 0.942 versus the control). During the infusion of a low [Cl(-)] solution (2.4 mM), the RMP moderately hyperpolarized to -0.9 ± 3.4 mV (n = 5; p < 0.01 versus the control), although the membranes, if governed by Cl(-) permeability, should be depolarized. These observations imply that the fibrocyte membranes are more permeable to Na(+) than K(+) and Cl(-), and this unique profile and [Na(+)] gradient across the membranes contribute to the positive RMP.
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Identification of a novel mutation in SLC26A4 gene in a Chinese family with enlarged vestibular aqueduct syndrome. Int J Pediatr Otorhinolaryngol 2016; 85:75-9. [PMID: 27240500 DOI: 10.1016/j.ijporl.2016.03.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/12/2016] [Accepted: 03/15/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To investigate the genetic causes of hearing loss in a two generation Chinese family with enlarged vestibular aqueduct syndrome (EVAS). METHODS Clinical and genetic evaluations were conducted in a deaf proband and her normal-hearing parents. Sanger sequencing analysis of all the 21 exons, the exon-intron boundaries and the promoter in SLC26A4 gene was performed to detect the pathogenic mutations. PCR-restricted fragment length polymorphism (PCR-RFLP) was used to further identify the mutation. Phylogenetic analysis was carried out with multiple sequence alignment using BioEdit software. Three-dimensional (3D) modeling of the human wild-type and mutant SLC26A4 (NP_000432.1) was carried out using I-TASSER (http://zhanglab.ccmb.med.umich.edu/). RESULTS Clinical examinations showed that the proband suffered from typical features of sensorineural hearing loss with enlarged vestibular aqueduct. A novel nonsense mutation c.2118C>A (p.C706X) in exon 19 was identified in compound heterozygosity with the splice-site mutation c.919-2A>G in the proband by using Sanger sequencing. The mother was a heterozygous carrier of c.919-2A>G in intron 7, while the father was a heterozygous carrier of c.2118C>A. The mutation c.2118C>A was not found in 200 unrelated controls using Sanger sequencing. PCR-RFLP showed the PCR product of the proband was not digested at 2110 by Fau I because of the c.2118C>A mutation. 3D-structure modeling indicated that the mutation c.2118C>A resulted in a truncate Pendrin protein. Protein alignment indicated high conservation of p.C706 residue in healthy Homo, Nomascus, Pan, Macaca, Canis, Sus, Mus, Rattus, Cricetulus and Xenopus. CONCLUSIONS This study revealed a novel heterozygous mutation c.2118C>A (p.C706X) compound with c.919-2A>G in SLC26A4 gene in a patient with EVAS.
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Slc26a4 expression prevents fluctuation of hearing in a mouse model of large vestibular aqueduct syndrome. Neuroscience 2016; 329:74-82. [PMID: 27155149 DOI: 10.1016/j.neuroscience.2016.04.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 12/13/2022]
Abstract
SLC26A4 mutations cause fluctuating and progressive hearing loss associated with enlargement of the vestibular aqueduct (EVA). SLC26A4 encodes a transmembrane anion exchanger called pendrin expressed in nonsensory epithelial cells of the lateral wall of cochlea, vestibular organs and endolymphatic sac. We previously described a transgenic mouse model of EVA with doxycycline (dox)-inducible expression of Slc26a4 in which administration of dox from conception to embryonic day 17.5 (DE17.5) resulted in hearing fluctuation between 1 and 3months of age. In the present study, we hypothesized that Slc26a4 is required to stabilize hearing in DE17.5 ears between 1 and 3months of age. We tested our hypothesis by evaluating the effect of postnatal re-induction of Slc26a4 expression on hearing. Readministration of dox to DE17.5 mice at postnatal day 6 (P6), but not at 1month of age, resulted in reduced click-evoked auditory brainstem response (ABR) thresholds, less fluctuation of hearing and a higher surface density of pendrin expression in spindle-shaped cells of the stria vascularis. Pendrin expression in spindle-shaped cells was inversely correlated with ABR thresholds. These findings suggest that stabilization of hearing by readministration of dox at P6 is mediated by pendrin expression in spindle-shaped cells. We conclude that early re-induction of Slc26a4 expression can prevent fluctuation of hearing in our Slc26a4-insufficient mouse model. Restoration of SLC26A4 expression and function could reduce or prevent fluctuation of hearing in EVA patients.
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Abstract
The identification of transcriptional differences has served as an important starting point in understanding the molecular mechanisms behind biological processes and systems. The developmental biology of the inner ear, the biology of hearing and of course the pathology of deafness are all processes that warrant a molecular description if we are to improve human health. To this end, technological innovation has meant that larger scale analysis of gene transcription has been possible for a number of years now, extending our molecular analysis of genes to beyond those that are currently in vogue for a given system. In this review, some of the contributions gene profiling has made to understanding developmental, pathological and physiological processes in the inner ear are highlighted.
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Affiliation(s)
- Thomas Schimmang
- Instituto de Biología y Genética MolecularUniversidad de Valladolid y Consejo Superior de Investigaciones CientíficasValladolidSpain
| | - Mark Maconochie
- School of Biological and Chemical SciencesQueen Mary University of LondonLondonUK
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de Moraes VCS, Bernardinelli E, Zocal N, Fernandez JA, Nofziger C, Castilho AM, Sartorato EL, Paulmichl M, Dossena S. Reduction of Cellular Expression Levels Is a Common Feature of Functionally Affected Pendrin (SLC26A4) Protein Variants. Mol Med 2016; 22:41-53. [PMID: 26752218 DOI: 10.2119/molmed.2015.00226] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/04/2016] [Indexed: 11/06/2022] Open
Abstract
Sequence alterations in the pendrin gene (SLC26A4) leading to functionally affected protein variants are frequently involved in the pathogenesis of syndromic and nonsyndromic deafness. Considering the high number of SLC26A4 sequence alterations reported to date, discriminating between functionally affected and unaffected pendrin protein variants is essential in contributing to determine the genetic cause of deafness in a given patient. In addition, identifying molecular features common to the functionally affected protein variants can be extremely useful to design future molecule-directed therapeutic approaches. Here we show the functional and molecular characterization of six previously uncharacterized pendrin protein variants found in a cohort of 58 Brazilian deaf patients. Two variants (p.T193I and p.L445W) were undetectable in the plasma membrane, completely retained in the endoplasmic reticulum and showed no transport function; four (p.P142L, p.G149R, p.C282Y and p.Q413R) showed reduced function and significant, although heterogeneous, expression levels in the plasma membrane. Importantly, total expression levels of all of the functionally affected protein variants were significantly reduced with respect to the wild-type and a fully functional variant (p.R776C), regardless of their subcellular localization. Interestingly, reduction of expression may also reduce the transport activity of variants with an intrinsic gain of function (p.Q413R). As reduction of overall cellular abundance was identified as a common molecular feature of pendrin variants with affected function, the identification of strategies to prevent reduction in expression levels may represent a crucial step of potential future therapeutic interventions aimed at restoring the transport activity of dysfunctional pendrin variants.
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Affiliation(s)
- Vanessa C S de Moraes
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Nathalia Zocal
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Jhonathan A Fernandez
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Charity Nofziger
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Arthur M Castilho
- Otology, Audiology and Implantable Ear Prostheses, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Edi L Sartorato
- Center of Molecular Biology and Genetic Engineering (CBMEG), Molecular Biology Laboratory, State University of Campinas, UNICAMP, Campinas/São Paulo, Brazil
| | - Markus Paulmichl
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
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Prosser JD, Cohen AP, Greinwald JH. Diagnostic Evaluation of Children with Sensorineural Hearing Loss. Otolaryngol Clin North Am 2015; 48:975-82. [DOI: 10.1016/j.otc.2015.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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50
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Cazals Y, Bévengut M, Zanella S, Brocard F, Barhanin J, Gestreau C. KCNK5 channels mostly expressed in cochlear outer sulcus cells are indispensable for hearing. Nat Commun 2015; 6:8780. [PMID: 26549439 PMCID: PMC4659937 DOI: 10.1038/ncomms9780] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/01/2015] [Indexed: 01/03/2023] Open
Abstract
In the cochlea, K(+) is essential for mechano-electrical transduction. Here, we explore cochlear structure and function in mice lacking K(+) channels of the two-pore domain family. A profound deafness associated with a decrease in endocochlear potential is found in adult Kcnk5(-/-) mice. Hearing occurs around postnatal day 19 (P19), and completely disappears 2 days later. At P19, Kcnk5(-/-) mice have a normal endolymphatic [K(+)] but a partly lowered endocochlear potential. Using Lac-Z as a gene reporter, KCNK5 is mainly found in outer sulcus Claudius', Boettcher's and root cells. Low levels of expression are also seen in the spiral ganglion, Reissner's membrane and stria vascularis. Essential channels (KCNJ10 and KCNQ1) contributing to K(+) secretion in stria vascularis have normal expression in Kcnk5(-/-) mice. Thus, KCNK5 channels are indispensable for the maintenance of hearing. Among several plausible mechanisms, we emphasize their role in K(+) recycling along the outer sulcus lateral route.
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Affiliation(s)
- Yves Cazals
- Laboratoire de Neurosciences Intégratives et Adaptatives (UMR7260), Fédération de Recherche 3C (Cerveau, Comportement, Cognition), Aix-Marseille-Université and CNRS, Marseille 13331, France
| | - Michelle Bévengut
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (UMR7286), Aix-Marseille-Université and CNRS, Marseille 13344, France
| | - Sébastien Zanella
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (UMR7286), Aix-Marseille-Université and CNRS, Marseille 13344, France
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille 13005, France
| | - Frédéric Brocard
- Institut de Neurosciences de la Timone (UMR7289), Aix-Marseille Université and CNRS, Marseille 13005, France
| | - Jacques Barhanin
- Laboratoire de Physio-Médecine Moléculaire (UMR7370), Université de Nice-Sophia Antipolis and CNRS, Nice 06107, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, France
| | - Christian Gestreau
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (UMR7286), Aix-Marseille-Université and CNRS, Marseille 13344, France
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